1. Field of the Invention
The invention relates to a manufacturing method for a secondary battery and a secondary battery. To be in more detail, the invention relates to a manufacturing method for a secondary battery, and a secondary battery having an electrode body that is made by laminating positive and negative electrode plates while sandwiching a separator between the positive and negative electrode plates.
2. Description of Related Art
A secondary battery is made by housing an electrode body inside a battery case together with an electrolytic solution. For example, the electrode body is structured by laminating belt-like positive and negative electrode plates while sandwiching a separator between the positive and negative electrode plates, each of the positive and negative electrode plates being made by forming an active material layer containing an active material on a surface of current collector foil. Japanese Patent Application Publication No. 2014-38736 (JP 2014-38736 A) is listed as an example of a prior art related to a secondary battery having such an electrode body.
In JP 2014-38736 A, a secondary battery is described, which includes a laminated electrode assembly (an electrode body) inside a case, the electrode assembly being made by flat lamination of positive and negative electrode plates together with separators. In JP 2014-38736 A, in each of the electrode plates, there is a portion where an active material layer is not formed, thereby exposing current collector foil, and the portion projects more than a portion where the active material layer is formed. In the electrode body, an electrode tab is formed by bundling the exposed portions of the current collector foil in a projecting state.
In JP 2014-38736 A, the electrode tab is connected with a terminal provided in a cover member that closes an opening of the case in which the electrode body is inserted. Further, the secondary battery according to the JP 2014-38736 A has a film that covers the electrode body and is fixed to the cover member or the terminal. It is stated that, when inserting the electrode body in the case, the electrode body is inserted while the film covering the electrode body is receiving a load of the electrode body. It is thus possible to prevent the load of the electrode body from being applied onto the electrode tab, thereby restraining breakage of the electrode tab.
When the electrode body is inserted into the case from the opening of the case, a pressing load for pressing the electrode body towards the case is applied to the electrode body. In the related art like the one stated above, when inserting the electrode body into the case, an insertion load is applied normally to a side surface of the electrode body on the side where the electrode tab projects, out of the outer surface of the electrode body. However, strength of the side surface of the electrode body is not so high because the side surface is structured from end portions of the electrode plates and the separators. Thus, there was a possibility that the end portions of the electrode plates and the separators on the side surface of the electrode body, to which the insertion load is applied, could be deformed due to bending or breakage, and, due to the deformation of the electrode plates and the separators in the electrode body, quality of the secondary battery could be deteriorated.